String deformation (string case switching and realization)

Supplement basic knowledge ：

JAVA in String Class provides methods for converting to uppercase toUpperCase() And the method of converting to lowercase toLowerCase()

String a = "ABC";
system.out.println(a.toLowerCase());//abc
String b = "abc";
system.out.println(b.toUpperCase());//ABC

Exercise description ：

 describe 
 For a length of  n  character string , We need to deform it .

 First of all, the string contains some spaces , It's like "Hello World" equally , Then what we need to do is reverse order the words separated by spaces in this string , Invert the case of each character at the same time .

 such as "Hello World" After deformation, it becomes "wORLD hELLO".

Code ：

package com.example.test;

import java.util.Scanner;

public class test {

    public static void main(String[] args) {

        System.out.println(" Please enter the fields you want to reverse ");
        Scanner scanner = new Scanner(System.in);

        while (scanner.hasNext()) {

            String st = scanner.nextLine();


            int len = st.length();
            System.out.println(" The length is " + len);
            String ll= tanstring(st, len);

            System.out.println(" The converted value is "+ll);
        }

    }

    private static String tanstring(String st, int se) {

        String res = "";
        String tempStr = "";
        for (int i = 0; i < se; i++) {
            char c = st.charAt(i);//i  For the length  st Enter content for  charAr  Similar to getting subscripts 

            if (c >= 'a' && c <= 'z') {
                tempStr += Character.toUpperCase(c);  //java  Method body   Convert upper case to lower case 
            } else if (c >= 'A' && c <= 'Z') {
                tempStr += Character.toLowerCase(c); //java  Method body   Lower case to upper case 
            }
            // hither   The above method completes the case switching   Separate each word   Size switch 
            // Here's how   Sequential switching 
            // String splicing   After each cycle  tempStr The values of are obtained last   The last value obtained is spliced in the front   You can achieve sequential switching 
            else {
                tempStr = c + tempStr;
                // Save the value of the last cycle 
                res = tempStr + res;
                tempStr = "";
            }


        }
        res = tempStr + res;
        System.out.println(" The output data is " + res);

        return res;
    }

}

The result is

 Please enter the fields you want to reverse 
Hello Word Yan
 The length is 14
 The output data is yAN wORD hELLO

Here is a debug Of Pictures are better understood Letter exchange